EP0622789B1 - Sheet-like structures containing side chain polymers - Google Patents

Description

The invention relates to two-dimensional structures consisting of side group polymers, the at least one photo-inducible configuration-changeable (1) and contain a permanently form-anisotropic side group (2) different from (1), which are connected to the main polymer chain via flexible spacer groups. In front The radiation-like structures according to the invention are in the glass state the polymers are optically isotropic, amorphous, transparent and non-light-scattering. By the radiation of the flat structures in the glass state of the polymers causes an alignment of the side groups photochemically, whereby the planar structures become birefringent and dichroic without their Losing transparency. The light-induced optical anisotropy can be thermal or can be reversibly modified or canceled by renewed irradiation.

The structures are suitable for reversibly storing and storing optical information manufacture passive or optically switchable components.

Various polymers with photochromic groups are known from the literature, their optical properties such as absorption, emission, reflection, birefringence or scattering by means of light-induced physical and / or chemical Processes can be changed reversibly. An interesting and novel method that Reversibly changing the optical properties of polymers consists in the light-induced variation of the degree of order, the direction and the Orientation distribution or the morphology of the polymer films by different Processes. The light-induced change in order in the polymer films serves to store the information.

Eich and Wendorff (Makromol. Chem., Rapid Commun. (1987) 8, 467) Liquid crystalline polymers containing azobenzene. These form liquid crystalline Domains in which only the groups are reoriented due to the influence of light that have previously undergone an isomerization reaction (Anderle, Birenheide, Wendorff, Makromol. Chem., Macromol. Symp. 44, 11-22 (1991)). The memory effect is based on the disturbance of the orderly state of the Monodomain through the reorientation of the photochromic side groups in one otherwise rigid matrix.

Stumpe et al. (Macromol. Chem., Rapid Commun., (1991), 12, Pp. 81-87) describe the irradiation of homeotropic liquid crystals or homogeneous monodomains of liquid crystals. This shows that always, materials with liquid crystalline order and no amorphous Materials are used. Anisotropy can be registered here, but the effects are not long-term stable. In addition, the production is uniformly oriented liquid-crystalline monodomains in the polymers are very complex.

In addition, liquid-crystalline polymers have recently become known, where the photochemical reorientation of the photochromic groups is a cooperative reorientation also causes non-photochromic groups, so that the optical axis of the monodomains is rotated. (Ivanov, Yakovlev, Kostromin, Shibaev, Läsker, Stumpe, Kreysig, Makromol. Chem., Rapid Commun. 12, 709-715 (1991)).

The serious application disadvantage of liquid crystalline systems is that that their use is generally a perfect, macroscopically uniform orientation through external fields and / or surface effects to a monodomain presupposes.

Orientation of liquid crystalline polymers through electrical and magnetic Fields as well as mechanical forces and surface effects are on the one hand Although methods have been introduced, they are also technologically exceptional complex, so that a wide application of such fabrics liquid-crystalline Polymers is not yet possible.

It was also found that in principle in an amorphous system Birefringence can be induced (Anderle, Birenheide, Eich, Wendorff, Makromol. Chem., Rapid, Comm. (1989) 10, 477ff and EP 335 302). However, the effect is orders of magnitude smaller than that of a liquid-crystalline monodomain received and therefore not technically usable.

It is also known (Natansohn, Rochon, Gosselin, Xie, Macromolecules 25, 2268-2273 (1992)) that certain homopolymers when irradiated with light can develop anisotropic properties.

Such a system is structurally invariant, not long-term stable and in its Properties set within wide limits. A particular advantage of copolymer systems versus the uniform polymers is just theirs Structural flexibility that allows the properties to be adapted to each Application purpose while maintaining the information-storing properties allowed.

For the technical usability of photo-addressable layers, it would be completely considerable advantage to have a system that looks like an optical one can handle isotropic, amorphous, homogeneous film and on the other hand over the outstanding dichroic and birefringent properties of a liquid crystalline Polymer film, combined with a certain range of Structural variation of the copolymers to the other properties of the material to be able to adapt to the respective technical requirements.

The object of the invention was to provide a system on the one hand provides optically isotropic flat structure, which on the other hand by action of light becomes dichroic and birefringent to an extent like this from very good liquid-crystalline systems is known.

This task is solved by a flat structure made up of side group copolymers and terpolymers, the photochromic Page groups and permanent shape anisotropic page groups with high Have anisotropy of molecular polarizability, in contrast to previously known photochromic liquid crystalline polymers and described Solution variants technologically variable and easily in optically isotropic, transparent, non-light-scattering, amorphous flat structures are transferred can.

Because the side group polymers have a number of structural features, Main polymer chain, different side groups, spacing groups between the Main chain and the side groups, end groups of the side groups, and the Structural elements influence each other, no fixed rule can be specified with which structural features with absolute certainty amorphous Flat structures are created. However, a number of Possibilities available, either through a suitable combination of Structural elements the kinetic suppression of the spontaneous formation of liquid crystalline Allow order states, or with amorphous polymers to produce the structural elements 1 and 2, for thermodynamic reasons do not develop liquid crystalline order states because they determine Contain structural elements that disrupt the tendency to order and for the further Examples are given below.

The finding and targeted manufacture of such amorphous systems is according to some orientation tests taking into account the following Teaching with sufficient certainty for success easily possible.

(1) das Seitengruppenpolymer enthält wenigstens eine photoinduzierbar konfigurationsveränderliche Seitengruppe;

(2) das Seitengruppenpolymer enthält wenigstens eine von (1) verschiedene permanent formanisotrope Seitengruppe mit hoher Anisotropie der molekularen Polarisierbarkeit;

(3) das Seitengruppenpolymer enthält zwischen Hauptkette und den Seitengruppen (1) und (2) flexible Abstandsgruppen;

dadurch gekennzeichnet, daß das flächenhafte Gebilde im Glaszustand der Seitengruppenpolymeren vor Bestrahlung optisch isotrop, transparent, nicht streuend und amorph und nach Bestrahlung transparent und durch eine im Glaszustand reversible lichtinduzierte Ausrichtung der Seitengruppen (1) und (2) langzeitstabil doppelbrechend und dichroitisch ist. The invention therefore relates to two-dimensional structures made of a polymer with a main chain and side groups branching off from the main chain (side group polymer) which have the following structural features (1) to (3):

(1) the side group polymer contains at least one photo-inducible configuration-changeable side group;

(2) the side group polymer contains at least one permanent form anisotropic side group different from (1) with high anisotropy of the molecular polarizability;

(3) the side group polymer contains flexible spacer groups between the main chain and the side groups (1) and (2);

characterized in that the sheet-like structure in the glass state of the side group polymers is optically isotropic, transparent, non-scattering and amorphous before irradiation and transparent after irradiation and is birefringent and dichroic in the long term with a reversible light-induced orientation of the side groups (1) and (2).

Photo-inducible groups that can be changed in configuration are e.g. Groups that Contain double bonds, their cis and trans configuration by the action of light can be converted into one another. These groups can also have one have high molecular shape anisotropy, but this is not permanent.

Permanent shape anisotropic groups are e.g. Groups that have a rigid, rod-shaped Have a rod-like shape, e.g. Bisphenylgruppen, Benzoic acid anilide groups or benzoic acid phenyl ester groups.

(a) es werden wenigstens zwei Arten von Abstandsgruppen (3) unterschiedlicher Länge eingebaut;

(b) wenigstens ein Teil der Abstandsgruppen (3) weist Heteroatome auf;

(c) wenigstens ein Teil der Abstandsgruppen (3) weist Verzweigungen auf;

(d) wenigstens ein Teil der Seitengruppen (1) oder (2) weist Verzweigungen auf;

(e) wenigstens ein Teil der Seitengruppen (1) oder (2) endet in verzweigten Endgruppen;

(f) wenigstens ein Teil der Monomerbausteine des Seitengruppenpolymers bildet keine flüssig-kristallinen Phasen aus;

(g) das Seitengruppenpolymer enthält eine weitere Seitengruppe (5), die keine permanente Formanisotropie aufweist.

Thermodynamically, the formation of liquid-crystalline order states becomes impossible due to the fact that the two-dimensional structure made of polymers has one or more structural features (4) from groups (a) to (g):

(a) at least two types of spacer groups (3) of different lengths are installed;

(b) at least some of the spacer groups (3) have heteroatoms;

(c) at least some of the spacer groups (3) have branches;

(d) at least some of the side groups (1) or (2) have branches;

(e) at least part of the side groups (1) or (2) ends in branched end groups;

(f) at least some of the monomer units of the side group polymer do not form liquid-crystalline phases;

(g) the side group polymer contains a further side group (5) which has no permanent shape anisotropy.

The polymers are particularly characterized in that they have the Structural elements 1 and 2 with high molecular shape anisotropy and high Anisotropy of molecular polarizability included, but that from the Shape anisotropy and other intermolecular interactions of the Side groups resulting tendency of the formation of liquid crystalline Order states effectively suppressed by the structural features a-g.

The claimed two-dimensional structures thus combine the good optical properties Properties of amorphous films and their compared to liquid crystalline Monodomain films with significantly simplified technological production high values of light-induced optical anisotropy, as previously only in Monodomains of liquid crystalline polymers were known.

• daß durch die Strukturelemente a-g die Ordnungstendenz der Polymere weitestgehend abgebaut wird und die Polymere nur noch geringe Phasenübergangsenthalpien aufweisen (ΔH<0,8 J/g), oder
• daß durch sehr starke zwischenmolekulare Wechselwirkungen der Seitengruppen 1 und 2, in den Beispielen bei den Polymere mit Wasserstoffbrückenbildung und CT-Wechselwirkungen realisiert, die Ausbildung einer lichtstreuenden Polydomänenstruktur unterdrückt wird, oder
• daß durch eine hohe Viskosität der isotropen Polymerfilme oberhalb des Klärpunktes, in den Beispielen durch Polymere mit kurzen Spacern oder steifen Polymerhauptketten realisiert, ebenfalls die Ausbildung der lichtstreuenden flüssigkristallinen Polydomänenstruktur unterdrückt wird,
• die Polymere durch rasches Abkühlen aus der isotropen Schmelze in den Glaszustand zu optisch isotropen, homogenen, nicht lichtstreuenden Filmen eingefroren werden.

Kinetically, the formation of liquid crystalline order states in the claimed two-dimensional structures of liquid crystalline polymers can be suppressed by

• that the structural tendency ag degrades the order tendency of the polymers as far as possible and that the polymers have only low phase transition enthalpies (ΔH <0.8 J / g), or
• that the formation of a light-scattering polydomain structure is suppressed by very strong intermolecular interactions of side groups 1 and 2, in the examples in the case of polymers with hydrogen bonding and CT interactions, or
• that the high viscosity of the isotropic polymer films above the clearing point, in the examples realized by polymers with short spacers or rigid polymer main chains, also suppresses the formation of the light-scattering liquid-crystalline polydomain structure,
• the polymers are frozen by rapid cooling from the isotropic melt into the glass state to form optically isotropic, homogeneous, non-light-scattering films.

In a further preferred embodiment of the invention the main chain the side group polymer of monomers, the side group (1) over spacer group (3), from monomers that carry the side group (2) through spacer groups (3) wear and optionally other monomers are formed, in particular the proportion of the monomers having the side group (1) is 10 to 80 mol%, the proportion of the monomers which have the side group (2), 20 to 90 mol% and the proportion of the other monomers are 0 to 50 mol%.

S₁, S₂

eine abstandshaltende Gruppe,

Q₁, Q₂

-O-, -CO-O-, -O-CO-, -CO-NR₁-, -NR₁-CO- oder -NR₁-,

P

eine photoinduzierbar konfigurationsveränderliche Gruppe,

M

eine von P verschiedene, permanent formanisotrope Gruppe,

X₁, X₂

ein endständiger Substituent und

R₁

Wasserstoff oder C₁-C₄-Alkyl bedeuten.

The sheetlike structure of the invention preferably consists of a side group polymer in which the main chain is a poly (meth) acrylate, a polysiloxane, a poly-α-oxirane, a polyether, a polyamide, a polyurethane, a polyester or a polycarbonate Side group (1) including the flexible spacer group (3) of the formula (I) and the side group (2) including the flexible spacer group (3) of the formula (II) correspond to: -S ₁ -Q ₁ -PX ₁ -S ₂ -Q ₂ -MX ₂ wherein

S ₁ , S ₂

a spacing group,

Q ₁ , Q ₂

-O-, -CO-O-, -O-CO-, -CO-NR ₁ -, -NR ₁ -CO- or -NR ₁ -,

P

a photo-inducible configuration-changeable group,

M

a permanently shape-anisotropic group other than P,

X ₁ , X ₂

a terminal substituent and

R ₁

Is hydrogen or C ₁ -C ₄ alkyl.

S₁, S₂

eine gegebenenfalls durch -O-, -NH- oder -Si(R₅)₂- unterbrochene Gruppe -(CH₂)_n-,

n

2 bis 14,

P

-Ar(N=N-Ar)_m-, -ArN=CR₂-Ar-, -Ar-CR₂=N-Ar-, -Ar-CR₂=CR₃-COOR₄-, -AR-(CH=CH-Ar)_m, -ArCR₂=CR₃-Ar, -Ar-CR₂=CR₃-COR₄ oder -Ar-CR₂=CR₃-Cyclohexyl,

R₂, R₃, R₄

H, C₁-C₄-Alkyl, CN, OR₂, COOR₄, Halogen, NO₂ oder N(R₅),

R₅

H oder C₁-C₄-Alkyl,

Ar

ein gegebenenfalls substituiertes aromatisches Ringsystem mit 5 oder 6 Ringgliedern,

m

1 oder 2,

M

ein Derivat des Cholesterols oder des Cholestans oder eine der Gruppen -Ar-Ar-, -Ar-Y-Ar-, Ar-Y-Alk-, -Alk-Y-Ar-, -Alk-Ar- oder -Ar-Alk-,

Y

-CO-O-, -OCO-, -CONH-, -NHCO-, -N=CH-, -CH=N-, -N-NO-, -C(R₅)₂-, -C(R₅)₂-C(R₅)₂-, -O- oder -NR₁-,

Alk

eine geradkettige, verzweigte oder cyclische, gegebenenfalls substituierte, gegebenenfalls olefinisch ungesättigte aliphatische Gruppe mit 1 bis 14 C-Atomen,

X₁, X₂

Wasserstoff, CN, Alk, Y-Alk, Aryl, Y-Ar, -N(Alk)₂, Halogen oder NO₂ bedeuten,

insbesondere ein solches, bei dem die Hauptkette ein Poly(meth)acrylat ist,

P

-Ar-(N=N-Ar)_m-, Ar-CR₂=CR₃-Ar- oder -Ar-CR₂=CR₃-COOR₄,

M

einen Rest des Biphenyls, eines Benzoesäureanilids oder eines Benzoesäurephenylesters,

X₁, X₂

H, CN, C₁-C₈-Alkyl, C₁-C₈-Alkoxy, C₅-C₇-Cycloalkoxy, Phenyl, Phenoxy, C₁-C₄-Di-alkylamino oder Nitro bedeuten.

A planar structure is preferred in which

S ₁ , S ₂

a group which may be interrupted by -O-, -NH- or -Si (R ₅ ) ₂ - - (CH ₂ ) _n -,

n

2 to 14,

P

-Ar (N = N-Ar) _m -, -ArN = CR ₂ -Ar-, -Ar-CR ₂ = N-Ar-, -Ar-CR ₂ = CR ₃ -COOR ₄ -, -AR- (CH = CH-Ar) _m , -ArCR ₂ = CR ₃ -Ar, -Ar-CR ₂ = CR ₃ -COR ₄ or -Ar-CR ₂ = CR ₃ -cyclohexyl,

R ₂ , R ₃ , R ₄

H, C ₁ -C ₄ alkyl, CN, OR ₂ , COOR ₄ , halogen, NO ₂ or N (R ₅ ),

R ₅

H or C ₁ -C ₄ alkyl,

Ar

an optionally substituted aromatic ring system with 5 or 6 ring members,

m

1 or 2,

M

a derivative of cholesterol or cholestane or one of the groups -Ar-Ar-, -Ar-Y-Ar-, Ar-Y-Alk-, -Alk-Y-Ar-, -Alk-Ar- or -Ar-Alk -

Y

-CO-O-, -OCO-, -CONH-, -NHCO-, -N = CH-, -CH = N-, -N-NO-, -C (R ₅ ) ₂ -, -C (R ₅ ) ₂ -C (R ₅ ) ₂ -, -O- or -NR ₁ -,

auk

a straight-chain, branched or cyclic, optionally substituted, optionally olefinically unsaturated aliphatic group with 1 to 14 C atoms,

X ₁ , X ₂

Are hydrogen, CN, alk, Y-alk, aryl, Y-ar, -N (alk) ₂ , halogen or NO ₂ ,

especially one in which the main chain is a poly (meth) acrylate,

P

-Ar- (N = N-Ar) _m -, Ar-CR ₂ = CR ₃ -Ar- or -Ar-CR ₂ = CR ₃ -COOR ₄ ,

M

a residue of the biphenyl, a benzoic acid anilide or a benzoic acid phenyl ester,

X ₁ , X ₂

H, CN, C ₁ -C ₈ alkyl, C ₁ -C ₈ alkoxy, C ₅ -C ₇ cycloalkoxy, phenyl, phenoxy, C ₁ -C ₄ di-alkylamino or nitro.

The side group polymer preferably has a glass transition temperature Tg of 40 40 ° C.

The individual structural elements of the polymers are known per se. To the ones you want To get combinations of properties, the specific molecular Structure of the individual polymer building blocks in relation to the others in the polymer included structural elements. The concrete structure of individual polymer building blocks is therefore variable within wide limits. The properties of these polymer films, their properties largely due to weak intermolecular interactions can not be determined by summing the Predict properties of individual molecular building blocks.

Decisive for the inventive solution is the planned and purposeful combination of the individual structural elements in the polymers in order to obtain the optically isotropic flat structures claimed. In the claimed two-dimensional structures, the structural elements with high shape anisotropy and high anisotropy of molecular polarizability are the prerequisite for high values of optical anisotropy. The structure of the polymers adjusts the intermolecular interactions of the structural elements (1) and (2) so that the formation of liquid-crystalline order states is suppressed and optically isotropic, transparent, non-scattering films can be produced. On the other hand, the intermolecular interactions are nevertheless strong enough that, when irradiated with polarized light, completely surprising and unpredictable, a photochemically induced, cooperative, directed reorientation process of the photochromic and the non-photochromic side groups is effected. This also determines the glass transition temperature of the polymers, which allows the order states to freeze below T _g .

The optically isotropic planar structures claimed according to the invention become thus formed from side group polymers whose morphological, dynamic, combination of photochemical and optical properties Structural elements and the setting of the intermolecular existing between them Interactions an efficient and long-term stable induction and modification of optical anisotropy in amorphous flat structures allow and combine opposing properties.

Weak interaction forces preferably occur between the side groups (1) and (2) enough that the photo-induced configuration change the side group (1) causes a reorientation of the side group (2) in the same direction.

Surprisingly, it was found that in the claimed optically isotropic Amorphous sheetlike structures of these photochromic polymers are extremely high Optical anisotropy values could be induced (Δn = 0.01 to 0.2). The Values are comparable to those in monodomains of liquid crystalline polymers have been preserved or even larger than this. They are significantly larger in Compared to amorphous polymers without these structural elements.

Due to the influence of actinic light in the flat structures Order states are generated and modified and thus the optical properties of the flat structures modulated.

Linear or circularly polarized light is preferably used as light, whose wavelength is photoinducible in the region of the absorption band configuration-changeable page groups (1).

The preparation of the side group polymers and their polymerization are described in processes known from the literature (DD 276 297, DE 3 808 430, macromolecular Chemie 187, 1327-1334 (1984), SU 887 574, Europ. Polym. 18, 561 (1982) and Liq. Cryst. 2, 195 (1987)).

The production of perfect, macroscopically uniform films is possible without complex Orientation procedure using external fields and / or surface effects are necessary. They can be spin coated, dipped, poured or other technologically easily controllable coating processes Apply documents by pressing or flowing between two transparent ones Bring plates or simply as a free-standing film by casting or extrusion prepare. Such films can be cooled suddenly, i.e. by a cooling rate of> 100 K / min, or by quickly removing the solvent also produce from liquid-crystalline polymers, the structural elements in the contain inventive sense.

The layer thickness is preferably between 0.1 μm and 1 mm, especially between 0.5 and 100 µm.

The light-induced orientation of the page groups or the registration of Information is provided by irradiation with the configuration-changeable for the photo-inducible Group of suitable actinic light. This leads to a angle-dependent photoselection, which realigns the photochromic Groups and - through a cooperative effect - a continuous, rectified Reorientation of the permanently form anisotropic side groups to maximally perpendicular to the electrical vector of the excitation light.

When polarized light is irradiated in the surface normal of a film you get a preferred orientation at the film level, which in the case of linear polarized light is uniform throughout the film while using circular polarized light the preferred direction according to the electrical Vector of the excitation light periodically modulated along the surface normal becomes. Irradiation with unpolarized light creates a preferred orientation perpendicular to the film plane.

The light exposure takes place flat or locally with linearly or circularly polarized, coherent or non-coherent, mono- or polychromatic light, whose wavelength in the absorption range of the photo-inducible configuration changes Page groups.

The information is written in a punctiform manner with a laser or flat with a laser or a lamp or using a mask at an intensity of 0.1 to 5,000 mW / cm ² in a time between 0.1 and 6000 seconds.

The process of reorientation is extremely effective. The achievable birefringence change at T «Tg it is preferably between Δn = 0.05 to 0.20.

The high values of the photochemically induced birefringence and the photochemically induced dichroism result from the molecular structure of the Side groups, the cooperative mechanism of light-induced orientation to a state of the same macroscopic orientation of the photochromic and non-photochromic, but permanently shape-anisotropic side groups as well as the Overcoming the limits of the reorientation process, as in liquid crystalline Monodomains exist because of the intermolecular interaction forces of the liquid-crystalline guest-host system is the primary one Stabilize the order of the ordered structure.

The preferred orientation is freely selectable, it depends solely on the choice of direction of the electrical vector of the excitation light with respect to the polymer body from. The degree of orientation is at constant temperature and Wavelength depends only on the incident energy, which is either over the Time or the power of the light source can be varied. So they are Orientation, birefringence and dichroism freely selectable parameters, which are under constant conditions with repeated enrollment and delete can be reproduced exactly. The photochemically induced optical Anisotropy remains at temperatures below after switching off the light source maintain the glass transition temperature of the polymer with long-term stability.

The effects are temperature dependent. When comparing the effects in different The glass transition temperature Tg serves as a reference point for polymers. The size of the maximum inducible optical anisotropy initially increases when the temperature rises on. In the case of amorphous polymers, it drops drastically in the glass temperature range. In the case of the amorphously frozen liquid-crystalline polymers, it also increases above Tg further with the temperature to finally near the Clearing point completely to disappear. Against this is the information registered - regardless of the temperature at which they were generated - and during storage the polymer films are stable for years at temperatures T <Tg.

In the polymers of the sheetlike structure according to the invention, a reproducible, defined, continuous tunable, long-term stable birefringence can be generated. She leaves in transmission or reflection in polarized light as a defined contrast represent. When using polymers whose side groups are dichroic Properties, a dichroism of absorption or the emission is reproducible, defined, continuously tunable and long-term stable produce. Through uniform radiation conditions, the whole Polymer film creates a uniform orientation. With local variation of the radiation conditions how energy dose and polarization direction becomes one with regard the preferred orientation of the side groups creates structured film, which leads to pixels with different optical anisotropy.

The orientations can be generated by heating the polymers via the Glass temperature or, if they form thermotropic mesophases, above the clearing point delete all or part. The energy required can be thermal or be supplied to a suitable light source.

The preferred direction in the orientation distribution of the optically anisotropic film can also be reversed by exposure to unpolarized actinic light made and the optical isotropy along the surface normal restored become. Re-irradiation with the same source, but different Position of the electrical vector in relation to the polymer film leads to a modification the direction and size of the optical anisotropy. In this way can vary between different states regarding the direction and size of the optical anisotropy can be switched repeatedly.

On the basis of these effects, the two-dimensional structures according to the invention stand out Medium for the reversible, optical data storage available. As with the Even after the information has been deleted, all measures are no longer required to produce the films to restore the monodomain.

The flat structures according to the invention can be used for digital or analog data storage in the broadest sense, for example for optical signal processing, for Fourier transformation and folding or in coherent optical correlation technology, use. The lateral resolution is determined by the wavelength of the Reading light limited. It allows a pixel size down to 0.5 µm. The maximum Contrast is 1: 200. This means that up to 100 shades of gray can be created in one pixel reproducibly enroll, thereby reducing the storage density for digital storage is increased.

This property makes the flat structures according to the invention for processing Images and particularly suitable for information processing using holograms, whose reproduction can be done by illuminating with a reference wave. The interference pattern of two in-phase monochromatic can be analogously save coherent light sources and through the connection between the electrical vector of light and the associated preferred direction in the Storage medium generate a higher storage density. According to save three-dimensional holographic images. The reading is done by Illumination of the hologram with monochromatic, coherent light. In the Analog storage can provide gray scale values continuously and locally can be set. Analog information stored is read out in polarized light, depending on the position of the polarizers the positive or bring out the negative image. Here, on the one hand, by the Contrast created by phase shift of ordinary and extraordinary beam of the film can be used between two polarizers, the levels of the Polarizers advantageously an angle of 45 ° to the polarization plane of the inscription light form and the polarization plane of the analyzer either perpendicular or is parallel to that of the polarizer. Another possibility is the Detection of the deflection angle of the induced by birefringence Reading light.

The flat structures according to the invention can be used as optical components, that can be passive or optically switchable. So the high light-induced optical anisotropy for modulating the intensity and / or the polarization state be used by light. Accordingly, one can from a polymer film produce components by holographic structuring, the imaging properties that are comparable to lenses or grids.

worin

R₁ und R₂

unabhängig voneinander H oder CH₃,

R₃

R₄

L₁ und L₃

unabhängig voneinander eine gegebenenfalls durch 1 bis 3 O-Atome unterbrochene Alkylengruppe mit 2 bis 14 C-Atomen

L₂

eine direkte Bindung, -CO-NH-, -NH-CO-, -CO-O- oder -O-CO-

R₅ und R₆

unabhängig voneinander einen Substituenten, insbesondere H, CN, C₁-C₆-Alkyl, C₁-C₆-Alkoxy, Di-C₁-C₄-alkylamino, Halogen oder Nitro und

x und y

0,1 bis 0,9 bedeuten,

wobei x + y = 1 und
die Monomerbausteine im Seitengruppenpolymer statistisch verteilt sind. Particularly preferred side group polymers corresponding to the formula (III)

wherein

R ₁ and R ₂

independently of one another H or CH ₃ ,

R ₃

R ₄

L ₁ and L ₃

independently of one another an alkylene group with 2 to 14 C atoms which may be interrupted by 1 to 3 O atoms

L ₂

a direct bond, -CO-NH-, -NH-CO-, -CO-O- or -O-CO-

R ₅ and R ₆

independently of one another a substituent, in particular H, CN, C ₁ -C ₆ alkyl, C ₁ -C ₆ alkoxy, di-C ₁ -C ₄ alkylamino, halogen or nitro and

x and y

Mean 0.1 to 0.9,

where x + y = 1 and
the monomer units in the side group polymer are statistically distributed.

Examples A. Synthesis of polymerizable monomers example 1 4-Cyano-4 '- (2-hydoxy-ethyloxy) diphenyl

3.0 g of KOH, 10 g of NC-C ₆ H ₄ -C ₆ H ₄ -OH and 6.15 g of ClCH ₂ CH ₂ -OH are dissolved in 50 ml of methanol in succession in a glass ampoule. The ampoule is filled with argon, melted and kept at 115 ° C. for 50 h. After opening the ampoule, 5 times the amount of CHCl _{3 is} added in a separatory funnel and shaken out with water. After separation, the organic phase is dried with MgSO ₄ .

After the solvent has been stripped off, the product is purified by chromatography and then recrystallized once from benzene.
Yield: 10.4 g (85% of theory)
F. 150 ° C
K 122 ° CN 126 ° CI

F: Schmelzpunkt

K: Kristallin

G: Glaszustand

N: Nematische Phase

S: Smektische Phase

I: Isotrope Schmelze

In this and the following examples, the abbreviations used have the following meanings:

F: melting point

K: Crystalline

G: glass state

N: Nematic phase

S: Smectic phase

I: Isotropic melt

Figures in parentheses indicate monotropic phases.

4- (6-Hydroxy-hexyloxy) -4'-cyanoazobenzene is prepared analogously.
Yield: 9.4 g (58.5% of theory)
F .: 150 ° C

Example 2 4-Cyano-4 '- (6-hydroxy-hexyloxy) -diphenyl

A mixture of 25 ml of ethyl methyl ketone, 10 g of HO-C ₆ H ₄ -C ₆ H ₄ -CN, 7.1 g of K ₂ CO ₃ and 13.9 g of HO- (CH ₂ ) ₆ -Br is stirred and refluxed heated to complete conversion (control by thin layer chromatography). The precipitate is then filtered off, the solvent is completely removed, the product is purified by chromatography and recrystallized once from benzene.
Yield: 13.4 g (81% of theory)
K 97 ° CS 112 ° CI

4- (2-Hydroxy-ethyloxy) -4'-cyanoazobenzene is prepared analogously .
Yield: 1.5 g (36% of theory)
F .: 184 ° C

Example 3 4-cyano -4 '- (2-acryloyloxyethyloxy) diphenyl

2.8 g of NC-C ₆ H ₄ -C ₆ H ₄ -O- (CH ₂ ) ₂ -OH in a mixture of 40 ml of absolute benzene and 1.95 ml of dry triethylamine are slowly added with the exclusion of moisture with stirring and heating ( 60 to 70 ° C) a solution of 1.4 ml of ClOC-CH = CH ₂ in 2 ml of absolute benzene. After stirring at 60 to 70 ° C for 2 h, the reaction mixture is diluted with 200 ml of CHCl ₃ , washed with water, dried with MgSO ₄ and the solvent is evaporated off. The product is recrystallized twice from methanol.
Yield: 2.67 g (78% of theory)
F .: 97.2 ° C

4-Cyano-4 '- (2-methacryloyloxyethyloxy) diphenyl is prepared analogously .
Yield: 1.4 g (69% of theory)
F .: 86 to 88 ° C

4- (2-Acryloyloxy-ethyloxy) -4'-cyanoazobenzene is prepared analogously .
Yield: 0.67 g
F .: 133.7 ° C

4- (2-Methacryloyloxy-ethyloxy) -4'-cyanoazobenzene is prepared analogously .
Yield: 0.78 g (89% of theory)
F .: 139.5 ° C

4-Cyano-4 '- (6-acryloyloxy-hexyloxy) diphenyl is prepared analogously .
Yield: 3.2 g (86.4% of theory)
K 87.5 ° C (N 80 ° C) I

Example 4 β- [4- (4'-cyano) diphenyloxy] ethyl-β'-chloro-ethyl ether

The product is prepared from NC-C ₆ H ₄ -C ₆ H ₄ -OH and ClCH ₂ CH ₂ -O-CH ₂ CH ₂ -Cl analogously to Example 1.
Yield: 7.8 g (50.5% of theory)
F .: 58 to 61 ° C

Analogously, 4- (β'-chloroethyloxy-ethyl-β-oxy) -4'-cyanoazobenzene is produced.
Yield: 4.6 g (42% of theory)
F .: 95 to 96 ° C

Example 5 4- (β'-methacryloyloxy-ethyloxy-ethyl-β-oxy) -4'-cyanoazobenzene

To a solution of 2 g Cl-CH ₂ CH ₂ -O-CH ₂ CH ₂ -OC ₆ H ₄ -N = NC ₆ H ₄ -CN in 10 ml dry hexamethylphosphoric triamide is 1.49 g (0.012 mol) dry powder of H ₂ C = C (CH ₃ ) COOK added while stirring and excluding moisture. After stirring for 1 h at room temperature and 1 h at 70 ° C, the reaction mixture is mixed with 5 times the amount of CHCl ₃ in a separatory funnel and extracted with water. After separation, the organic phase is dried with MgSO ₄ . After the solvent has been stripped off, the product is recrystallized twice from methanol.
Yield: 1.9 g (84% of theory)
F .: 74.0 ° C

4- (β'-Acryloyloxy-ethyloxy-ethyl-β-oxy) -4'-cyanoazobenzene is prepared analogously .
Yield: 1.63 g (74% of theory)
F .: 113.5 ° C

Β [4- (4'-Cyanodiphenyl) oxy] ethyl-β'-methacryloyloxyethyl ether is prepared analogously .
Yield: 6.63 g (76% of theory)
F .: 64 ° C

Analogously, β [4- (4'-cyanodiphenyl) oxy] ethyl-β'-acryloyloxyethyl ether is prepared.
Yield: 0.88 g (71% of theory)
F .: 62 ° C

Example 6 4- (6-methacryloyloxyhexyloxy) benzoic acid-4-n-methoxyanilide

55.4 g methacrylic acid, 15 g 4- (6-hydroxyhexyloxy) benzoic acid, 2.25 g hydroquinone, 2.25 g of p-toluenesulfonic acid and 150 ml of chloroform were used a water separator is boiled under reflux for 18 hours and then mixed with 1.66 g of sodium acetate trihydrate in 5 ml of water. chloroform and unreacted methacrylic acid were removed in a rotary evaporator. The reaction product was taken up in 750 ml of chloroform and filtered. After washing the reaction product with 100 ml of water, drying over Sodium sulfate and filtration a crystalline product was obtained at -18 ° C filtered, washed with toluene and recrystallized from toluene. To Drying gave 15 g of 4- (6-methacryloyloxyhexyloxy) benzoic acid (F .: 92 ° C).

These were dissolved in 30 ml of thionyl chloride, a few drops of N, N-dimethylformamide and some 2,4-di-tert-butylphenol were added and the mixture was converted into the acid chloride by stirring for two hours. After the excess thionyl chloride had been stripped off, the product was taken up in 25 ml of chloroform and added dropwise at 0 to 5 ° C. to a stirred solution of 1.85 g of p-anisidine and 3 ml of triethylamine in 50 ml of chloroform. The mixture was stirred at room temperature for 3 hours. The solution was washed several times with water, dried over sodium sulfate and then the solvent was distilled off. The reaction product was recrystallized from isopropanol.
Yield: 4.4 g (69% of theory)
F .: 134 to 135 ° C

4- (6-Methacryloyloxyhexyloxy) -benzoic acid-4-n-pentoxyanilide is prepared analogously .
Yield: 4.4 g (71% of theory)
F .: 132 to 133 ° C

Example 7 4- (6-methacryloyloxyhexyloxy) benzoic acid-4-cyanoanilid

12 g of 4- (6-methacryloyloxyhexyloxy) benzoic acid were converted into the acid chloride analogously to Example 6. This was taken up in 100 ml of benzene and added dropwise at room temperature with stirring to a solution of 4.6 g of 4-amino-benzonitrile in 12.5 ml of pyridine and 125 ml of benzene. The mixture was stirred for a further 3 hours and the reaction mixture was left to stand overnight. The precipitate was filtered off and recrystallized from toluene and methanol.
Yield: 10.7 g (67.3% of theory)
F .: 132 to 133 ° C

Example 8 4- (6-methacryloyloxyhexyloxy) benzoic acid-4-n-butoxyphenylester

6.1 g of 4- (6-methacryloyloxyhexyloxy) benzoic acid were converted into the acid chloride as in Example 6. This was taken up in 100 ml of dry tetrahydrofuran (THF) and added dropwise at 0 to 5 ° C. to a stirred solution of 3.3 g of hydroquinone monobutyl ether in 100 ml of THF and 4 ml of triethylamine. The mixture was stirred at room temperature for three hours and then the precipitated triethylamine hydrochloride was filtered off. The filtrate was evaporated to dryness and the residue was dissolved in 50 ml dichloromethane. The solution was washed several times with water, dried with sodium sulfate and then the solvent was distilled off. The crude product obtained was purified by column chromatography and by recrystallization from n-hexane.
Yield: 6.3 g (66.7% of theory)
F .: 57 to 58 ° C

Example 9 4- (2-Methacryloyloxyethyloxy) -azobenzene

A mixture of 0.4 mol of 1,2-dibromoethane, 0.2 mol of potassium carbonate, 0.004 mol of 4-hydroxyazobenzene, a trace of potassium iodide and 200 ml of acetone was heated under reflux for 6 hours by stirring. After cooling, it was filtered. The residue obtained after distilling off the solvent was recrystallized from methanol.
Yield: 8.3 g (68% of theory)
F .: 79 to 85 ° C

A mixture of 11.4 g of this product and 0.075 mol of potassium methacrylate was stirred in 100 ml of N, N-dimethylformamide (DMF) at 60 ° C. for ten hours. After cooling, the mixture was diluted with water, the precipitate formed was filtered off and air-dried. The crude product was purified by column chromatography and by recrystallization from tert-butanol.
Yield: 8.1 g (70%)
F .: 65 to 67 ° C

B. copolymerization and polymer characterization Example 10

A solution of 0.247 g of 4-cyano-4 '- (2-methacryloyloxyethyloxy) diphenyl and 0.076 g of 4- (β'-methacryloyloxy-ethyloxy-ethyl-β-oxy) -4'-cyanoazobenzene in 2.9 ml absolute benzene was obtained after thoroughly rinsing the reaction vessels and Mixtures with nitrogen by adding 0.0064 g of azoisobutyronitrile (AIBN) brought to polymerization as a polymerization initiator at 70 ° C. The Response time was 45 hours. The reaction product was with ethanol precipitated, filtered off and dissolved in 1,2-dichloroethane. That from the filtered again Polymer obtained solution was reprecipitated from ethanol and in vacuo Dried and degassed at 120 ° C. The yield was 95% of theory.

Polymers of the formula (IV) were obtained in an analogous manner by copolymerization. The results can be found in Table 1. No. x y m n R ¹ Tg
(° C) phase tc
(° C) 1 0.6 0.4 2 2 H 85 LC 106.2 2 0.6 0.4 2 6 H 67 LC 108.1 3 0.6 0.4 2 2 CH ₃ 107 LC 127.7 4 0.6 0.4 2 6 CH ₃ 93 LC 118.8 Tg is the glass temperature, Tc the clearing temperature.

LC within the "Phase" column means that the corresponding polymer is below Tc forms liquid-crystalline phases.

Polymers of the formula (V) were obtained in an analogous manner. The results can be found in Table 2. No. x y n R ¹ Tg
(° C) phase tc
(° C) 5 0.6 0.4 2 CH ₃ 86 amorphous - 6 0.8 0.2 6 CH ₃ 68 amorphous - 7 0.9 0.1 6 CH ₃ 66 amorphous - 8th 0.6 0.4 6 CH ₃ 62 LC 86

Polymers of the formula (VI) were obtained in an analogous manner. The results can be found in Table 3. No. x y m R ¹ Tg
(° C) phase tc
(° C) M _w
(10g / mol) 9 0.8 0.2 2 CH ₃ 101 amorphous - 2.12 10 0.6 0.4 2 CH ₃ 88 amorphous - 1.94 11 0.4 0.6 2 CH ₃ 77 amorphous - 1.67 12 0.2 0.8 2 CH ₃ 67 LC 89.7 1.64 13 0.4 0.6 6 CH ₃ 57 LC 102.4 - 14 0.8 0.2 2 H 77 LC 91.3 2.20 15 0.6 0.4 2 H 70 LC 87.2 - 16 0.4 0.6 2 H 60 LC 78.1 - 17 0.2 0.8 6 H 54 LC 83.1 - 18 0.4 0.6 6 H 43 LC 97.0 -

Example 11

A solution of 1.134 g of 4- (6-methacryloyloxyhexyloxy) benzoic acid 4-n-methoxyanilide and 0.776 g of 4- (2-methacryloyloxyethyloxy) azobenzene in 19 ml of DMF after rinsing the reaction tubes and mixtures thoroughly Nitrogen by adding 0.0164 g AIBN as a polymerization initiator at 70 ° C brought to polymerization. The reaction time was 24 hours. The The reaction product was precipitated with 500 ml of ethanol, filtered off and in 20 ml DMF solved. The polymer obtained from the re-filtered solution was made Ethanol fell over and dried in vacuo at 120 ° C and degassed. The Yield was 1.34 g (70% of theory).

Polymers of the formula (VII) were obtained in an analogous manner. The results can be found in Table 4. No. x y R ² Tg
(° C) phase tc
(° C) M _w
(10 ⁴ g / mol) M _w / Mn 19 0.7 0.3 OC ₅ H ₁₁ 75 LC 102 9.4 2.95 20 0.5 0.5 OC ₅ H ₁₁ 81 amorphous - 8.7 2.80 21 0.76 0.24 CN 97 amorphous - 183.7 17.30

Polymers of the formula (VIII) were obtained in an analogous manner. The values are given in Table 5. No. x y Tg
(° C) phase tc
(° C) 22 0.7 0.3 55 LC 89 23 0.6 0.4 59 LC 83 24 0.5 0.5 63 amorphous - 25 0.4 0.6 64 amorphous -

Example 12

The composition of the copolymers obtained was determined by elemental analysis and UV / Vis spectroscopy.

The number average M _n and the weight average M _{w of} the molecular weights were determined by GPC measurements. The figures given are relative values based on a polystyrene standard measured under the same conditions. The M _n values were additionally determined by membrane osmometry.

The determination of the phase transition temperatures or the exclusion of existence Thermotropic mesophases were carried out by polarization microscopic examinations and DSC measurements. The latter were also used to determine the Glass temperatures used.

C) Preparation of amorphous films Example 13

Two glass plates were covered with polyimide film at a distance of 15 µm held and fixed with the help of epoxy resin.

A melt of the amorphous polymer 5 was caused by the action of capillary forces placed at 150 ° C between the plates.

After cooling to room temperature, a transparent, optically complete clearer, bubble-free, non-scattering and optically isotropic in all spatial directions Received film.

This amorphous body showed no birefringence and pointed under the polarizing microscope no domain structure. Also a conoscopic view showed that the film was optically isotropic and thus amorphous.

This result was also confirmed by polarized UV / Vis measurements and by polarized IR measurements confirmed. The "degree of order" determined in this way of the polymer was 0.

In an analogous manner, films of the polymers 6, 7, 9 to 11, 20 and 21 with the get described properties.

Example 14

A melt of polymer 1 was contributed by the action of capillary forces Brought 150 ° C between the plates prepared as in Example 13.

After the sudden cooling to room temperature, a transparent, optically completely clear, bubble-free, non-scattering and optically in all Isotropic film obtained in spatial directions.

This amorphous body showed no birefringence and pointed under the polarizing microscope no domain structure. Also a conoscopic view showed that the film was optically isotropic and thus amorphous.

This result was also confirmed by polarized UV / Vis measurements and by polarized IR measurements confirmed. The "degree of order" determined in this way of the polymer was 0.

In an analogous manner, films of the polymers 2 to 4, 8 and 12 to 19 with the get described properties.

Example 15

Amorphous films of polymer 19 on silica glass and silicon substrates were made produced by spin coating.

A solution of 4% by weight of the polymer in THF was fritted through a poration of 10 microns filtered.

The silica glass and silicon wafers used as the carrier material for the films were pre-rinsed with THF in the spin coater before coating.

The solutions of the polymer were applied to the resting substrate, which was then set in rotation (5000 rpm; time approx. 1 min).

The films were kept in the dark for 10 hours under a solvent-free gas stream stored.

In this way, transparent, optically completely clear films were obtained no domain structure or birefringence under the polarizing microscope exhibited. Conoscopic studies showed that the films are optically isotropic and were therefore amorphous. Polarized UV / Vis (glass substrates) or FTIR measurements (Si substrates) support this finding. FTIR stands for Fourier transform Infrared spectroscopy.

The film thicknesses were measured with a Talystep device. she were approximately 500 nm.

In an analogous manner, films of the polymers 1 to 19 and 20 to 24 with the described properties obtained on silica glass and silicon substrates. The Layer thicknesses were in the range of 400 to 1000 nm by choosing the Concentration and the speed of rotation set.

Example 16

An amorphous film of polymer 20 was filtered from a 20% by weight Solution of the polymer made in THF.

A silica glass substrate was coated with this solution so that it was homogeneous and was free of bubbles. Then the solvent became slow evaporated and the plate for 10 h in the dark under a solvent-free Gas flow stored.

The layer thickness was about 5 µm. The film was optically clear and showed below the domain polarization microscope has no domain structure or birefringence. The Conoscopic examination showed that the film is optically isotropic and therefore amorphous was. Polarized UV / Vis measurements confirm this finding.

D) Interaction of the amorphous films with actinic light Example 17

The polymer 19 was irradiated in a cell produced as in Example 14 with the linearly polarized light of an Ar ⁺ laser (λ = 488 nm, P = 100 mW / cm ² ). During the irradiation, UV / Vis spectra were recorded with a measuring beam polarized parallel and perpendicular to the plane of polarization of the excitation light. It was found that after about 7 seconds a constant ratio of E and Z isomers of the azobenzene chromophores is established, which is no longer changed by further irradiation (photostationary equilibrium). The detected dichroism of the band attributable to the E isomer (r = A _∥ 365 nm / A _⊥ 365 nm) increased continuously from r = 1 to r = 1.9 during an irradiation time of 300 seconds, with A _∥ 365 nm the absorption in the perpendicular direction and A _┴ 365 nm means the absorption parallel to the polarization plane of the Ar ⁺ laser. This demonstrates that a continuous reorientation of the photochromic groups takes place when irradiated with linearly polarized light, which leads to the development of a preferred orientation in the film plane.

Under these conditions, everyone else shows a qualitatively analogous behavior Polymers.

Example 18

The polymer 20 was irradiated in a cell produced as in Example 13 with unpolarized light from an Ar ⁺ laser (λ = 488 nm, P = 100 mW / cm ² ). During the irradiation, UV / Vis spectra were recorded with measuring beams polarized in three different directions (horizontal, vertical and 45 ° to the horizontal). In the region of the band to be assigned to the E isomer, the absorption was independent of the polarization direction of the measuring beam. The sum of all three absorptions decreased continuously over an irradiation period of 300 seconds. This demonstrates that a continuous reorientation of the photochromic groups takes place when irradiated with unpolarized light, which leads to the formation of a preferred orientation perpendicular to the film plane.

Example 19

The polymer 21 was irradiated in the form of a layer on Si carrier as produced in Example 15 with the linearly polarized light of an Ar ⁺ laser (λ = 488 nm, P = 100 mW / cm ² ). During the irradiation, FTIR spectra were recorded with a measuring beam polarized parallel and perpendicular to the plane of polarization of the excitation light. The dichroism of the band assigned to the CN stretching vibration of the cyano group of the shape-anisotropic side group increased continuously during an irradiation time of 300 seconds from r = 1 to r = 1.9, where r = A _∥ / A _┴ and A _∥ the integral of _Represent the CN band with the measurement beam polarized perpendicular to the excitation light and A _┴ the integral of the CN band with the measurement beam polarized parallel to the excitation light. This demonstrates that when irradiated with linearly polarized light through a cooperative effect, the photo-induced movement of the photochromic groups causes a continuous, rectified reorientation of the shape-anisotropic, non-photochromic side groups up to a maximum perpendicular to the polarization plane of the excitation light.

The same behavior could be found for all other polymers become.

This cooperative effect in combination with the specific structure of the Polymers does this particularly in comparison with other amorphous polymers high values of inducible birefringence up to 0.11, which so far only due to macroscopic reorientation processes through external fields in Liquid crystals were observed.

Example 20

Amorphous films of polymers 5 to 7, 10, 11 and 20 to 25 produced according to embodiment 13 and amorphous films of polymers 1 to 4, 8 and 12 to 19 produced according to embodiment 14 were in the glass state with the expanded (d = 10 mm), linearly polarized light beam from an Ar ⁺ laser (λ = 488 nm; P = 200 mW / cm ² ) irradiated.

During the irradiation, the birefringence in the film plane was measured using a He / Ne laser (λ = 632.8 nm; P = 0.5 mW / cm ² ). This increased continuously from Δn = 0 (amorphous film) and aimed for a limit value Δn _max . The size of the limit value and the irradiation time required for this depended on the polymer structure, the temperature of the film, the layer thickness and the irradiation power.

Table 6 shows an example of the limit values of the birefringence achieved and the determined time constants for some of the experiments carried out. polymer P (mW / cm ² ) ϑ (° C) Δn _max τ (s) 1 200 20 0.065 +/- 0.005 40 +/- 3 2 200 20 0.053 +/- 0.002 66 +/- 3 3 200 20 0.066 +/- 0.002 50 +/- 2 4 200 20 0.052 +/- 0.002 150 +/- 20 5 200 20 0.047 +/- 0.004 30 +/- 3 6 200 20 0.039 +/- 0.001 210 +/- 10 7 200 20 0.033 +/- 0.002 1400 +/- 100 8th 200 20 0.053 +/- 0.002 105 +/- 5 9 200 20 0.040 +/- 0.003 120 +/- 20 10 200 20 0.050 +/- 0.002 52 +/- 4 11 200 20 0.080 +/- 0.004 29 +/- 3 12 200 20 0.081 +/- 0.007 9 +/- 1 13 200 20 0.065 +/- 0.007 47 +/- 4 14 200 20 0.058 +/- 0.003 140 +/- 14 15 200 20 0.078 + / 0.004 50 +/- 5 16 200 20 0.087 +/- 0.004 32 +/- 4 17 200 20 0.110 +/- 0.010 14 +/- 2 18 200 20 0.110 +/- 0.010 63 +/- 10 19 200 20 0.020 +/- 0.003 1280 +/- 100 19 200 50 0.040 +/- 0.004 240 +/- 20 20 200 20 0.025 +/- 0.002 550 +/- 50 20 200 50 0.040 +/- 0.005 240 +/- 20 21 200 20 0.025 +/- 0.002 320 +/- 30 21 200 50 0.040 +/- 0.005 150 +/- 10

After the irradiation there was a weak relaxation of the birefringence values from Δn _max to Δn _stab , whereby always (An Max -Δn Rod ) / .DELTA.n Max <0.05 was valid if Tg-T> 10K. The Δn _stab values remained constant during three years of storage at temperatures below Tg.

Microscopic observation showed qualitatively that the generated anisotropy was constant over the entire irradiated area.

The conoscopic examination of the irradiated film showed that in the film plane an optical axis was induced which is perpendicular to the plane of polarization of the actinic light.

Example 21

Ten amorphous films of polymer 20 produced according to embodiment 13 were under the conditions described in Example 20 with 10 different Directions of the plane of polarization are irradiated. In any case, in the amorphous films induced an optical axis perpendicular to the plane of polarization of the excitation light. The amount induced in relation to this axis the birefringence was under otherwise identical radiation conditions regardless of the direction of the polarization plane of the excitation light. This demonstrates that the direction of the axes of the optical anisotropy through the Choice of the plane of polarization of the excitation light in relation to the Polymer body is adjustable.

Example 22

A 15 μm thick film of polymer 19 prepared as described in Example 14 was irradiated with the expanded (d = 10 mm), linearly polarized light beam from an Ar ⁺ laser (λ = 488 nm; P = 200 mW / cm ² ). The birefringence was measured during the irradiation. The irradiation was interrupted in each case after a birefringence change of 0.0004 was achieved, the establishment of a stable birefringence after weak relaxation was waited for and then irradiated further. After 100 such steps, a birefringence of 0.04 was reached. This demonstrates that the extent of the orientation of the body which is amorphous in the initial state depends on the duration of the irradiation and can therefore be set as desired.

Example 23

Eight 15 μm thick films of polymer 20 prepared as described in Example 13 were irradiated with the expanded (d = 10 mm), linearly polarized light beam from an Ar ⁺ laser (λ = 488 nm) for 300 s each. The laser power was varied. The different birefringences induced in the process are summarized in the following table. P / mW / cm ² 1 2 5 10 20 50 100 200 .DELTA.n 0.0002 0.0004 0.0008 0,002 0,006 0.02 0.04 0.06

This demonstrates that the degree of orientation of the initial state amorphous body depends on the power of the excitation light and thus is freely adjustable.

Example 24

Two 15 μm thick films of polymer 19, prepared as described in Example 14, were coated with the expanded (d = 10 mm), linearly polarized light beam from an Ar ⁺ laser (λ = 488 nm) until an induced birefringence of An = 0 was reached. 02 irradiated. The first film was irradiated at room temperature (approx. 45 K below the glass temperature). An irradiation time of approx. 350 seconds was necessary to induce the desired birefringence. The second film was heated to 80 ° C (approx. 10 K above the glass temperature) immediately after the start of the irradiation. In this case, induction of the desired birefringence only took about 70 seconds. During the irradiation, this film was cooled again to room temperature, so that the relaxation after the end of the irradiation corresponded to that described in Example 20. This demonstrates that the optical anisotropy is registered at temperatures below the glass temperature or briefly above the glass temperature and is frozen in the glass state.

E) Targeted modification of the optical properties of the polymer body as a prerequisite for use in digital optical data storage Example 25

A 15 μm thick film of polymer 19 prepared as described in Example 14 was exposed at room temperature with the linearly polarized light beam of an Ar ⁺ laser (λ = 488 nm; P = 100 mW / cm ² , d = 1 mm) in ten different areas irradiated for different lengths of time. The induced birefringence was measured. The film was then heated above the glass transition temperature and cooled again to room temperature. Then the irradiation was carried out under the same conditions. The resulting birefringence deviated from each other by a maximum of 2% of the absolute value for the same irradiation time. This demonstrates that a reproducible, defined birefringence is produced in the polymer, which leads to a defined, readable contrast in comparison to the unirradiated polymer film using two polarizers located in a defined position relative to one another and to the polymer film.

Example 26

A 15 μm thick film of polymer 20, prepared as described in Example 13, was coated at ten different areas at room temperature with the linearly polarized light beam of an Ar ⁺ laser (λ = 488 nm; P = 100 mW / cm ² , d = 1 mm) irradiated with ten different directions of the polarization plane (10 ° steps from horizontal to vertical direction) for 300 seconds each. The polymer film was between two crossed polarizers. The intensity of a He / Ne laser radiating perpendicularly through this arrangement was measured. The film was then heated above the glass transition temperature and cooled again to room temperature. Then the irradiation was repeated under the same conditions. This procedure was carried out ten times in a row. The intensities of the He / Ne laser beam measured after the different irradiations on the same areas differed by a maximum of 2% from one another. This demonstrates that a reproducible, defined birefringence is generated in the polymer, which leads to a defined, readable contrast in comparison to the unirradiated polymer film and to areas irradiated with other polarization planes using two polarizers located in a defined position relative to one another and to the polymer film.

Example 27

A 15 μm thick film of polymer 19 prepared as described in Example 14 was subjected to ten times different lengths at room temperature with the linearly polarized light beam of an Ar ⁺ laser (λ = 488 nm; P = 100 mW / cm ² , d = 1 mm) irradiated. After each irradiation, the anisotrope of the absorption was determined by UV / Vis spectroscopy, the polymer film was heated above the glass temperature and cooled again to room temperature. Then came the next radiation. The ten cycles were repeated three times. It was found that the measured absorption deviated from each other by a maximum of 2% for each polarization direction of the measuring beam with the same irradiation time. The anisotropy of the absorption increased with increasing radiation duration. This increase was in good agreement with the increase in birefringence with increasing radiation time (see example 22). After the last irradiation, the polymer film was stored for 6 months in the dark at room temperature without the absorption anisotropy changing significantly. This demonstrates that a reproducible, defined, continuously tunable, long-term stable dichroism of absorption is generated in the polymers.

Example 28

A 15 μm thick film of polymer 20, prepared as described in Example 13, was coated ten times at room temperature with the linearly polarized light beam of an Ar ⁺ laser (λ = 488 nm; P = 100 mW / cm ² , d = 10 mm) with different polarization directions Irradiated for 300 seconds. The polarization directions were the same as those in Example 26. After each irradiation, the anisotropy of the absorption was determined by UV / Vis spectroscopy, the polymer film was heated above the glass transition temperature and cooled again to room temperature. Then came the next radiation. The ten cycles were repeated three times. It was found that the amounts of the measured anisotropies of absorption differed by a maximum of 2% for all 40 irradiations. The direction of the maximum absorption was perpendicular to the direction of polarization of the excitation light, that of the minimum absorption parallel to it. No dichroism could be detected before the first irradiation and after the heating and subsequent cooling of the polymer film. This demonstrates that a reproducible, defined dichroism of the absorption is produced in the polymers, which is read out in transmission as a defined anisotropy of the absorption of the polymer film and which differs from that for the unirradiated polymer film or the areas irradiated with other polarization directions.

Example 29

A 15 μm thick film of polymer 19 prepared as described in Example 14 was treated ten times at room temperature with the linearly polarized light beam of an Ar ⁺ laser (λ = 488 nm; P = 100 mW / cm ² , d = 10 mm) with a different polarization direction Irradiated for 300 seconds. After each irradiation, the induced birefringence was measured and the polymer film was viewed orthoscopically and conoscopically under the microscope. The film was then heated above the glass transition temperature and cooled again to room temperature. Then the irradiation was repeated under the same conditions with the polarization direction changed by 10 °. The amount of birefringence and the microscopic appearance of the film was constant over the entire irradiated area. After the individual irradiations, the optical properties of the polymer film differed only by the direction of the optical anisotropy generated, corresponding to the selected direction of the polarization plane of the excitation light. This demonstrates that a uniform orientation can be produced in the entire polymer film by uniform irradiation conditions.

Example 30

100 different locations of a film of polymer 19 prepared as described in Example 14 were irradiated with the linearly polarized light beam of an Ar ⁺ laser (λ = 488 nm, P = 100 mW / cm ² , d = 10 µm) for different lengths of time. Pixels with different birefringence values were created. The irradiation times were chosen so that the Δn values resulted, which were already given in Example 22. This demonstrates that a film structured with respect to the local preferred orientation of the side groups is produced by pixel-wise variation of the irradiation time.

Example 31

A field of 8 by 8 dots (diameter 10 μm each) on a film of polymer 19 prepared as described in Example 13 was irradiated with the linearly polarized light beam of an Ar ⁺ laser (λ = 488 nm) pixel by pixel for 300 seconds each. In the first line of the field, the points were irradiated in the order of the columns with a power of 1, 2, 5, 10, 20, 50, 100 and 200 mW / cm ² . In the second line, the sequence 2, 5, 10, 20, 50, 100, 200, 1 mW / cm ^{2 was} selected, etc., until finally the individual columns of the eighth line with 200, 1, 2, 5, 10, 20, 50 and 100 mW / cm ^{2 were} irradiated. A pixel pattern was created, the birefringence of the individual pixels corresponding to the values for the associated laser power given in Example 23. This demonstrates that a film structured with regard to the local preferred orientation of the side groups is produced by pixel-wise variation of the radiation intensity.

Example 32

By irradiating ten pixels of a film of polymer 19 prepared as described in Example 13 with light (λ = 488 nm, P = 100 mW / cm ² , T _irr = 300 s), each has a different polarization direction with respect to the sample (0 ° to 90 ° in steps of 10 °), pixels with different preferred directions were generated in the film plane, which, from an orthoscopic point of view for extinction and amplification, showed a different behavior, corresponding to their orientation, with respect to the rotation between the polarizers. This demonstrates that a film structured with respect to the local preferred orientation of the side groups is produced by pixel-wise variation of the polarization direction of the excitation light.

Example 33

All of the anisotropic orientation distributions generated by radiation in Examples 20 to 32 could be eliminated by heating the polymers above the glass transition temperature and subsequent cooling (amorphous polymers) or heating above the clearing point and abrupt cooling below the glass transition temperature (liquid-crystalline polymers). After this treatment, the polymer bodies no longer differed in their spectroscopic and microscopic properties from the state before the irradiation. Of the pixels generated in Example 32, every second was removed by heating by means of irradiation with a CO ₂ laser (λ = 1060 nm, P = 1 W / cm ² , t _irr = 5 s). The result was a uniform isotropic film with the five birefringent pixels that were not irradiated with the CO ₂ laser. This demonstrates that all of the orientations generated or individual pixels are eliminated by surface or local heating, the required energy being supplied either directly or by means of a suitable light source, and the initial state is thus restored.

Example 34

The pixels which had not been erased with the CO ₂ laser after the irradiation described in Example 33 and which had been produced as described in Example 32 were treated with the unpolarized light beam from an Ar ⁺ laser (λ = 488 nm, P = 300 mW / cm ² , t _irr = 300 s) irradiated. After this irradiation, the pixels showed no birefringent properties when viewed perpendicularly. This demonstrates that preferred directions primarily generated by irradiation with unpolarized actinic light are canceled and the film becomes optically isotropic again along the normal.

Example 35

A 15 μm thick film of the polymer 20 prepared as described in Example 13 was irradiated at room temperature with the linearly polarized light beam of an Ar ⁺ laser (λ = 488 nm; P = 100 mW / cm ² , d = 10 mm) for 300 seconds. In this way a birefringence of 0.04 was induced. The optical axis generated in the polymer film was perpendicular to the plane of polarization of the excitation light. The polarization plane of the excitation light was then rotated through 45 ° and again irradiated for 300 seconds. A birefringence of 0.04 was induced, the optical axis generated being perpendicular to the plane of polarization of the excitation light, that is to say rotated by 45 ° in comparison with the result of the first irradiation. Now the polarization plane of the excitation light was rotated again by 45 ° in the same direction and irradiated again for 300 seconds. The result was a birefringence of 0.04, the optical axis generated being perpendicular to that induced after the first irradiation. By rotating the plane of polarization of the excitation light three times, each time by 30 °, followed by irradiation for 300 seconds in each case, the optical axis of the polymer film was brought into position again after the first irradiation via two intermediate stages. The same steps were then repeated with the direction of the polarization plane of the excitation light constant by rotating the polymer film about an axis parallel to the direction of propagation of the light. Both approaches led to identical results. This demonstrates that by re-irradiation with light from the same source but with a different polarization level or by changing the position of the polymer film in relation to the polarization level of the inscription light, it can be switched between different preferred directions and thus the optical anisotropy can be modified.

Example 36

100 different locations of a film of polymer 20 prepared as described in Example 14 were irradiated with the linearly polarized light beam of an Ar ⁺ laser (λ = 488 nm; P = 100 mW / cm ² , d = 10 µm) for different lengths of time. Pixels with different birefringence values were created. The irradiation times were chosen so that for the 15 μm thick film 100 discrete values of the phase shift for light of the wavelength 632.8 nm resulted, which were in the range between complete extinction and complete transparency for the sample between crossed polarizers. Scanning the polymer film with the beam of the He / Ne laser gave the intensities 0.01 I ₀ , 0.02 I ₀ , 0.03 I ₀ , .... 0.98 I ₀ , 0 for the individual pixels. 99 I ₀ , I ₀ , where I _{0 is} the measured intensity of the laser after passing through the amorphous film between parallel polarizers. This demonstrates that up to 100 different readable gray levels can be reproducibly written into one pixel.

Example 37

For pixel-by-pixel structuring, a film of polymer 19, produced as in Example 13, was applied at ten different points with a laser beam tapered to 100 µm (λ = 488 nm; P = 200 mW / cm ² ) for a constant time (t _irr = 300 s) ) exposed.

This resulted in ten pixels with identical values of birefringence orthoscopic and conoscopic viewing a similar behavior of rotation between crossed polarizers.

F) Storage of pictorial information Example 38

A pictorial information storage using a test mask was carried out in one film of polymer 1 prepared as described in Example 13 and in a Film of polymer 20 prepared as described in Example 16.

For this purpose, the test mask (line pair pattern) was fixed on the polymer preparation, so that it rested homogeneously (contact transfer).

The pictorial information contained in the mask was stored by irradiation with linearly polarized actinic light from an Ar ⁺ ion laser (λ = 488 nm; P = 100 mW / cm ² ), the beam of which was expanded for pictorial orientation in such a way that the pattern area was homogeneous was broadcast.

The irradiation time was 3 minutes, the film temperature was 10 K below respective glass transition.

After the irradiation, the information inscribed in the film was under viewed under the polarizing microscope. A resolution of 2 µm was no problem possible.

Example 39

A pictorial information storage was carried out as in Example 38 with the Difference that a photo negative was used instead of the test mask.

The inscribed images became visible between crossed polarizers as a negative (analogous to the original) and between parallel polarizers as a positive. According to the template, the information written has a continuous gray scale. This shows that any value of the birefringence can be set between 0 and Δn _max depending on the radiation dose.
The registered images have been stable for over a year.

G) Production of anisotropic optical components Example 40

For the generation of passive anisotropic optical components a Preparation of polymer 20 used as described in Example 14 was prepared (layer thickness 10 µm).

Irradiation was carried out with the linearly polarized expanded beam of an Ar ⁺ ion laser (P = 100 mW / cm ² ) until the birefringence generated by the light-induced orientation of the amorphous film at 633 nm caused a phase shift of λ / 4 or λ / 2 causes.

So the location of the polarization plane of the linearly polarized non-actinic Light can be rotated by 90 ° (λ / 2) or from linearly polarized light circular polarized are generated (λ / 4). These results were made by Intensity measurements checked on the analyzer.

H) measuring principles Example 41

The anisotropies of the polymer films generated in the exemplary embodiments 20 to 26, 29 to 31, 35 and 38 were detected during the irradiation by measuring the phase shift that the beam of an He / Ne laser (P = 1 mW / cm ² , λ = 633 nm, beam diameter d = 0.5 mm) with vertical transmission through the film. The plane of polarization of the measuring light formed the bisector between the two main axes of the anisotropy generated.

The intensity of the measuring beam was measured after passing through a Analyzer for four polar positions (0 ° and 90 ° as well as +/- 45 °). From the Intensities measured were intensity losses resulting from light scattering eliminated and the phase shift and birefringence using the Fresnell's equation calculated.

Example 42

The pictorial information (test mask, photonegative) stored in the polymer films according to working examples 38 and 39 was treated with non-actinic linearly polarized light from an expanded He / Ne laser (λ = 633 nm, P = 10 ^-3 mW / cm ² ) after the passage of an analyzer mapped flat on a screen.

Depending on the position of the polar to each other (0 ° or 90 °), the positive or Generate negative image of the mask or the photo.

I) Cyclic reversibility Example 43

In a film of polymer 10 produced in accordance with Example 13 and oriented in accordance with Example 29, the film was rotated at 90 ° in each case by irradiation with an argon ion laser (λ = 488 nm, P = 200 mW / cm ² , t = 90 s) Polarization level the refractive index anisotropy based on a fixed coordination system cyclically switched between -0.01 and +0.01. The time course of the phase shift and the maximum and minimum values of the transmission of the He / Ne laser by the arrangement of the polarizer-film analyzer was reproducible over 150 cycles with a deviation of less than 5%.

The radiation was applied in another experiment during one cycle interrupted at a point where the film showed no double calculation. This is synonymous with a photonic deletion of the stored information.

After such an interruption, the radiation was reduced by 90 ° rotated plane of polarization of the actinic light, could the birefringence can be achieved again that the film before the previous one Irradiation showed (0.01 or -0.01).

This proves a high cyclic reversibility of the systems and systems used shows the possibility of realizing reversible optical data storage and optically switchable anisotropic optical components based on these Systems.

K) Other actinic light sources Example 44

A flat orientation of the amorphous polymer films according to Example 29 was also obtained by irradiation with the linearly polarized light Mercury lamp (λ = 365 nm) realized.

Example 45

A pixel-wise orientation of the amorphous polymer films according to example 33 and cycling the pixels between different ones Orientation states according to Example 43 were determined by irradiation in Polarizing microscope (100 W halogen lamp as actinic radiation source) realized using a steep edge filter for the UV component.

L) Light sensitivity of the polymers Example 46

To estimate the sensitivity of the polymers, a film of polymers 10 and 11 prepared according to Example 14 and a film of polymer 12 prepared according to Example 13 were provided with the linearly polarized light of an Ar ⁺ ion laser (λ = 488 nm; P = 250 mW / cm ² ) irradiated until the light of the He / Ne laser suffered a phase shift of Δf = π / 6. The times required for this were measured and are summarized in the following table with the resulting energy doses. polymer 10 11 12 t (π / 6) / s 10.5 5.3 2.3 E = t P / Jcm ^-2 2.6 1.3 0.6

Example 47

A method was used to further assess the sensitivity of the polymers used, which leads to data that characterize the sensitivity of usual photographic films can be used. This method takes into account the specific effects that the photographic usability of the claimed polymers are based and thus differs from that for used conventional films.

For this purpose, the polymer films examined in Example 46 were irradiated up to a phase shift of π / 2 under the conditions described there. The transmission of the He / Ne laser through the system polarizer-polymer film analyzer (polarizer and analyzer crossed; direction of polarization of the inscription light is the bisector) and its decadal logarithm (log I / I _o ) against the decadal logarithm of the energy dose was measured (log E) plotted. Before the irradiation, log (I / I _o ) was _{E = O} = -2. This value is referred to as a gray haze when evaluating photographic films. The same value was also obtained by measuring the intensity without a polymer film located between the polarizing films. It is thus determined by the quality (degree of polarization) of these foils.

In the course of the irradiation, log (I / I _o ) rose to 0 almost linearly. The energy which was necessary to produce a change in the log (I / I _o ) which was above the noise was now determined. By definition, this is a change from {log (I / I _o )} _{E = O} to {log (I / I _o )} _{E = O} + 0.1. This energy dose H * is used in the sensitometric testing of photographic films to calculate the sensitivity S = 1 / H *. The following table summarizes the values of H * and S for the three polymers investigated. polymer 10 11 12 H * [Jcm ^-2 ] 0.59 0.40 0.19 S [cm ² J ^-1 ] 1.7 2.5 5.2

Claims (13)

1. A flat material made from a polymer with a backbone and side groups branching off the backbone (side group polymer), which polymer has the following structural features (1) to (3):

   (1) the side group polymer contains at least one photoinducibly configuration-changing side group;

   (2) the side group polymer contains at least one permanently conformationally anisotropic side group with high anisotropy of molecular polarisability which differs from (1);

   (3) the side group polymer contains flexible spacer groups between the backbone and the side groups (1) and (2) ;

   characterised in that the flat material in the glassy state of the side group polymers is optically isotropic, transparent, non-scattering and amorphous before irradiation and, after irradiation, is transparent and durably birefringent and dichroic due to a reversible, photoinduced alignment of the side groups (1) and (2) in the glassy state.
2. A flat material according to claim 1 which has at least one further structural feature (4) selected from the group (a) to (g) :

   (a) at least two kinds of spacer groups (3) of differing length are incorporated;

   (b) at least some of the spacer groups (3) have heteroatoms;

   (c) at least some of the spacer groups (3) are branched;

   (d) at least some of the side groups (1) or (2) are branched;

   (e) at least some of the side groups (1) or (2) are terminated with branched end groups;

   (f) at least some of the monomer units of the side group polymer do not form liquid crystalline phases;

   (g) the side group polymer contains further side groups (5) which do not exhibit permanent conformational anisotropy.
3. A flat material made from a side group polymer according to claim 1, characterised in that the backbone of the side group monomers is formed of monomers bearing the side groups (1) via spacer groups (3), of monomers bearing the side groups (2) via spacer groups (3) and optionally further monomers.
4. A flat material made from a side group polymer according to claim 3, characterised in that the proportion of monomers with side group (1) is 10 to 80 mol%, the proportion of monomers with side group (2) is 20 to 90 mol% and the proportion of further monomers is 0 to 50 mol%.
5. A flat material made from a side group polymer according to claim 1, characterised in that the backbone is a poly(meth)acrylate, a polysiloxane, a poly-α-oxirane, a polyether, a polyamide, a polyurethane, a polyester or a polycarbonate, the side group (1), including the flexible spacer group (3), corresponds to the formula (I) and the side group (2), including the flexible spacer group (3), corresponds to the formula (II): -S₁-Q₁-P-X₁ -S₂-Q₂-M-X₂ in which

   S₁, S₂

   mean a spacer group,

   Q₁, Q₂

   mean -O-, -CO-O-, -O-CO-, -CO-NR₁-, -NR₁-CO- or -NR₁-,

   P

   means a photoinducibly configuration-changing group,

   M

   means a permanently conformationally anisotropic group differing from P,

   X₁, X₂

   mean a terminal substituent and

   R₁

   means hydrogen or C₁-C₄ alkyl.

6. A flat material made from a side group polymer according to claim 5, characterised in that

   S₁, S₂

   mean a group -(CH₂)_n-, optionally interrupted with -O-, -NH- or -Si(R₅)₂-,

   n

   means 2 to 14,

   P

   means -Ar(N=N-Ar)_m-, -ArN=CR₂-Ar-, -Ar-CR₂=N-Ar-, -Ar-CR₂=CR₃-COOR₄, -AR-(CH=CH-Ar)_m, -ArCR₂=CR₃-Ar, -Ar-CR₂=CR₃-COR₄ or -Ar-CR₂=CR₃-cyclohexyl,

   R₂, R₃, R₄

   mean H, C₁-C₄ alkyl, CN, OR₂, COOR₄, halogen, NO₂ or N(R₅),

   R₅

   means H or C₁-C₄ alkyl,

   Ar

   means an optionally substituted aromatic ring system with 5 or 6 ring members,

   m

   means 1 or 2,

   M

   means a derivative of cholesterol or cholestane or one of the groups -Ar-Ar-, -Ar-Y-Ar-, -Ar-Y-Alk-, -Alk-Y-Ar-, -Alk-Ar- or -Ar-Alk-,

   Y

   means -CO-O-, -OCO-, -CONH-, -NHCO-, -N=CH-, -CH=N-, -N-NO-, -C(R₅)₂-, -C(R₅)₂-C(R₅)₂-, -O- or -NR₁-,

   Alk

   means an unbranched, branched or cyclic, optionally substituted, optionally olefinically unsaturated aliphatic group with 1 to 14 C atoms,

   X₁, X₂

   mean hydrogen, CN, Alk, Y-Alk, aryl, Y-Ar, -N(Alk)₂, halogen or NO₂.

7. A flat material made from a side group polymer according to claim 5, characterised in that the backbone is a poly(meth)acrylate,

   P

   means -Ar-(N=N-Ar)_m, -Ar-CR₂=CR₃-Ar- or -Ar-CR₂=CR₃-COOR₄,

   M

   means a residue of a biphenyl, benzoic acid anilide or a benzoic acid phenyl ester,

   X₁, X₂

   mean H, CN, C₁-C₈ alkyl, C₁-C₈-alkoxy, C₅-C₇ cycloalkoxy, phenyl, phenoxy, C₁-C₄ dialkylamino or nitro.

8. A flat material made from a side group polymer according to claim 1, characterised in that the side group polymers has a glass transition temperature T_g of ≥40°C.
9. A flat material made from a side group polymer according to claim 1, characterised in that weak interactive forces arise between side groups (1) and (2) which are sufficient to ensure that a photoinduced configuration change of side group 1 brings about an identically directed reorientation of side group 2.
10. A flat material according to claim 9, wherein the photoinduced configuration change of side group 1 and the identically directed reorientation of side group 2 bring about a change in birefringence of Δn = 0.01 to 0.2.
11. A flat material according to claim 1, produced by casting an isotropic melt of a side group polymer according to claim 1 and cooling at a rate of > 100 K/min.
12. A process for generating and modifying ordered states and for modulating the optical properties of the flat materials according to claims 1 to 10, characterised in that light acts upon the flat materials.
13. A process according to claim 12, wherein, depending on the effect to be achieved, the light is linearly or circularly polarised or unpolarised light of a wavelength range absorbed by side group (1).